Na +-K + Atpase and ouabain binding have been reported to be decreased in the kindled rat model of epilepsy. Na + -K + ATPase is involved in maintaining the membrane potential at 65mV. A decrease in the activity of the enzyme will cause depolarization of the cell membrane. Our work will involve the investigation of the status of the Na + -K + ATPase system in spiking and non spiking tissue from the human temporal lobe by measuring the activity of the enzyme as well as the binding of ouabain. An attempt will be made in these studies to demonstrate an alteration in the activity of the enzyme. Na + -K + ATPase activity is not altered in the kindled rat brain and ouabain binding is not altered in the human cortex. Such a lack of alteration may indicate that ATPase abnormalities occur in a very small number of cells and cannot be detected with current procedures. To determine if the ATPase has a role in the epileptic tissue from animals and human brain, kindled rats and human brain will be evaluated for ATPase activity as well as ouabain binding activity. The investigation of the activity of Na + -K + ATPase in the kindled rat brain and the human epileptic focus has been completed. No difference in the activity of ATPase were found in the human focus versus the nonfocus. The lack of difference between these tissues does not indicate a lack of involvement of this enzyme in the epileptic focus. One reason for the inability to find a difference could be that the alteration of the enzyme activity could be occurring in a minuscle area of the spiking brain region and cannot be detected with the presently available methods.